Which Intel mobile CPU consumes the least power.

JamesMJ

New Member

I'm looking at purchasing a new laptop for business. Battery life is the biggest concern. I'm trying to decipher which Intel processor is going to give me the best battery life. Speed, cache, FSB, etc. are all unimportant compared to Battery life. I have to admit, I got a little lazy, It wasn't easy for me to find the tech. docs on some of the processors. I'm hoping someone here maybe knows off hand. Thanks.

ThreeOnTheTree

New Member

From what I understand, you want the "Pentium M" paired with the older i855 chipset. The Pentium M should be 90nm, 2mb L2 cache, aka "Dothan," and the speed shouldn't really matter, since all PMs are rated with the same 21W TDP. What you definitly don't want is the P4M or any version of the Celeron, if battery life is your main concern. When shopping keep an eye out, as Intel recently launched a new chipset for notebooks, the i915. While it is faster and has a few more features than the i855, it also consumes more power (which reduces battery life).

Another thing to consider when buying for mobility is to upgrade to the 12 cell battery. Most notebooks ship with a 6 or 8 cell, which allows the OEM to keep the total price lower. Also, stay away from 7200rpm notebook drives, as they use more power as well.

JamesMJ

New Member

I have been looking at Toshibas. I would post a full link, but I'm in my IT class, and the lab computer is locked down. The model I'm interested in is the M45-S165. If you look up the specs it might list the mobo. Unfortunatly it ships with a 4 cell POS battery. The rated up time was an 1.5 hrs. Which means I might get an hour out of it. I need a bat that I can get at least 2.5 hrs out of. the optional 8 cell (for $144) supplies 2~3hrs of charge time.

DanceMan

Procrastinating Member

A recent report someone here (Three?) linked claimed that the best battery life among the Pentiums was with the i855 chipset, as Three mentioned, and with the 400MHz fsb Dothans, as opposed to the 533MHz fsb Dothans.
Intel also make a couple of ULV (ultra low voltage) Pentium M cpus. Finding which notebooks use them might not be easy.

JamesMJ

New Member

<laughs> No, Toshiba is pretty pricey. I'm just not a big fan of HP( I loathe the Desktop line) I was looking at Gateways too, Seeing as I like AMD in my desktops. One thing, It's very hard to tell on some manufacturers websites what the guts of the machine are. You get a lot of marketing and very little in the way of specs. Personally I'd rather have a 400FSB CPU, since the memory is all 333 anyway. At least what I've seen. I check the link for HP.

DanceMan

Procrastinating Member

We are the exceptions. Most people's eyes glaze over if you give them that information, and the manufacturers know it. You'd think they'd make it available somewhere, but their attitude seems to be "Who needs to know?"

ThreeOnTheTree

New Member

I don't mind HP's notebooks (and Compaq), really. They seem fairly well built, have lots of features, and the price is usually right. If I were to buy something for myself, I would get the 14" widescreen compaq, with a 1.8ghz Turion, 512mb RAM, 5400rpm drive, and the 12cell battery upgrade. By my best guess, I'd think it would be really fast, yet get 4-5 hours of use on a charge. It might also come in just under $1k. However, that may not be the best choice for you.

While it's true that there are ULV Dothans, I doubt you'd want to buy a system with one, since the ULVs are typically put in really small notebooks that have dinky batteries and limited options. A standard, 400fsb Dothan is the ticket, IMO. Up to the 12 cell, then configure the rest to fit your needs. Definetly get 512mb of RAM to reduce HD page swapping. 1GB is only necesary if you are using memory intensive programs while unplugged.

JamesMJ

New Member

Now that I've been turned onto HP, and we've discussed Intel CPUs, Are AMD's CPU offerings competitive? Forgive me, I should have asked sooner, just now noticed that HP actually offered an AMD based system. Also, since Intel has had a death grip on the mobile market for so long, I just assumed they remained the only real game in town.

ThreeOnTheTree

New Member

That's a harder question to answer, since there are very few reviews out there that test this out. Typically, the Intel-based notebooks have better battery life, though that advantage has been getting smaller and smaller. Where Intel still has the edge is in the chipset. Intel makes a mobile chipset and wireless adapters for "Centrino," while AMD's mobiles are paired with a variety of 3rd party chipsets and wifi's. While the Turion only consumes 25-35W (depending on the model), the chipset and wireless card might not be as efficient as Intel's. I'd say that typically, you will get probably about an hour less battery life with an AMD system vs a comperable Intel system. However, you will save $200-300 by going with a Turion. I guess that all depends on how important battery life is to you.

Hoyle

New Member

Now that I've been turned onto HP, and we've discussed Intel CPUs, Are AMD's CPU offerings competitive? Forgive me, I should have asked sooner, just now noticed that HP actually offered an AMD based system. Also, since Intel has had a death grip on the mobile market for so long, I just assumed they remained the only real game in town.

I'm sort of in charge of buying IT equiptment for my company. Generally speaking, We go Dell on the desktops (they are cheaper than dirt). We use IBM/Lenovo T&Ls (the X series, basically) but those have very limited features. We've used primarily Dell notebooks until recently. Lately, HP has been very cost competitive with Dell, and their build quality has definately had the upper hand for the last two or three model released. We have a number of the 6120s, and they've been pretty good mobility options. Get about 4 hours with the 8-cell batteries on those. Haven't tried the Turion model yet, but next time we order we probably will.

Generally, the Turion is a very powerful competitor - certainly it's performance is comperable with Dothan. There are some reviews that suggest that AMD's power management is a little better than Intels... that the 'light use' battery life on the Turion is actually better. I'm a bit skeptical. When I try it myself, I'll decide. However, there is no doubt then under constant load the Dothan will get an extra 25-30% of life on the battery.

If your big goal is 2.5 Hours, that's NOT hard to achieve with a Turion, but with battery life being your biggest concern, I'd pay a few hundred more for the Dothan.

This particular model is using the "Alvisio" 915GM chipset. So I bought into the marketing and went for the Centrino setup. I plan on getting some cheaper aftermarket RAM and going for a 1GB of PC3200 (2x512)

Couple things I am not sure on are the upgraded CPU, the HDD. I'm not sure the default Celeron CPU is a "Dothan" and I want to make sure I get a Dothan. If the Celeron is a Dothan core, it's probably not worth the cost to upgrade. You tell me? The harddrive is the other option. Not sure which way to go on that either. Is there a big hit in Batt. life getting the faster drive? Again you tell me.

DanceMan

Procrastinating Member

The Dothan is the second Pentium M core. The first was Banias. I think the Celeron M is just a Banias (they both have the 1Mb L2 cache) with the SpeedStepping disabled. The Dothan has a number of improvements beyond just the larger 2Mb cache.
A 5400 rpm drive shouldn't cost you much battery life, but will be noticably faster. I'd get it if the cost is reasonable.

Hoyle

New Member

Well, Celeron is the same basic 'core' as Dothan... but it's lacking 1/2 of the L2 cache. And this drops performance a good 10-12% at the same clockspeeds. So, a 1.6 GHz Celeron would probably be about the same performance as a 1.4 GHz Pentium-M Dothan. It's up to you which way you think makes more sense.

As far as the HDD, I'd go 5400 RPM. My laptop originally came with a 4200 RPM drive and I replaced it with a 5400 RPM drive. The battery life dropped about 15 minutes... about 8%. But applications load about 67% faster, I'd estimate, and general multitasking perfomance is MUCH better with the 5400 rpm disk. Of course, I also got one of the best disks Seagate made (a year ago). When I benched it, it was beating some 5400 RPM DESKTOP(!!!) drives. When you consider how much slower the media actually passes under the servo arm/heads of a 2.5" drive, that's really quite extraordinary.